1. Field of the Invention
This invention relates to a tension meter for orthopedic surgery for expanding a spacing between bones and measuring a degree of tension between the bones before embedding an artificial joint or implanting an artificial bone between the bones.
2. Description of the Prior Art
In recent years, various new materials such as ceramics have been developed, and skeletal alternative materials having an excellent function have also been proposed in succession. An artificial joint and an artificial bone to be manufactured by using such skeletal alternative materials are widely used in the field of orthopedic surgery at present, and a great remedial effect has been exhibited.
Such an artificial joint or an artificial bone is surgically embedded or implanted into a human body. For example, in the case of substituting the artificial joint for a knee joint, a spacing between bones in the knee joint is set before actually embedding the artificial joint. In this procedure, a distal portion of a femur and a proximal portion of a tibia are first cut away, and then a spacer having a suitable thickness is inserted into the spacing between the femur and the tibia. Under this condition, a surgeon checks the degree of tension of the ligaments connecting the femur and the tibia at opposite side portions of the knee joint by touching the ligaments with his fingers. Further, the surgeon measures the degree of tension of the ligaments with his senses by swinging a leg portion below the tibia in right, left, front and rear directions. As the tensile strength of the ligaments is individually dependent on patients, it is necessary to expand the spacing between the femur and the tibia to a suitable value according to the tensile strength of each patient and stretch the ligaments under a suitable tension, so as to make the artificial joint function properly. Accordingly, various spacers are provided having different thicknesses are used in succession to select an optimum one of these spacers and set the spacing between the femur and the tibia according to the tensile strength of PG,3 the ligaments of the patient. Thereafter, the selected spacer is removed from the knee joint, and an artificial joint having a size corresponding to the spacing set above is then embedded into the knee joint.